Beth:Building jigs is the story of my life (a dull life). Every new project requires new jigs.

About truss-rods, a few people use carbon fiber in the neck but I will let them present their own case. I have never used a stiffener on any of my ukuleles and have not had any problems so far. The total force from four strings is around forty pounds. There is not enough force to cause the neck to bend.

Bob is right, that the string tension on a uke isn't enough to require a truss rod. You can still do it if you want to and many of my father's custom ukes use them. Stick to carbon fiber for less weight if you decide to try it.